The image on the cover of Geology features a portion of this color panorama taken by NASA's Mars Exploration Rover Spirit. This full, 360-degree view combines 243 images taken by Spirit's panoramic camera over several martian days, or sols, from sol 318 (Nov. 24, 2004) to sol 325 (Dec. 2, 2004). It is an approximate true-color rendering generated from images taken through the camera's 750-, 530-, and 480-nanometer filters. Image credit: NASA/JPL-Caltech/Cornell

In a stunning panorama from Mars, a pair of corrugated tracks meander unevenly toward a distant hill and pink horizon across an untouched terrain of reddish soil and small, jagged stones.

Nearly two years after landing, NASA's Mars Exploration Rovers still dazzle the public. The pair of tracks featured on the cover of the October, 2005 issue of the scientific journal Geology are just one example. Images from the rovers have adorned the covers of Science, Nature, and many other publications. Hundreds of thousands of viewers visit the NASA's Mars Rover web pages every month.

No mission has roamed the surface of another planet for so long.

"We are essentially doing a natural history expedition to another world, much like explorers a century or two ago in the American West and other unexplored lands," says Larry Crumpler, a geologist at the New Mexico Museum of Natural History and Science who recommended the cover image.

"I think the continued interest says that this mission is something different. People are telling me all the time that they check in on the Mars Exploration Rovers Web site daily to see what the rovers are doing."

New Mexico Panorama

High school science teacher Joe Aragon is joined by students from Laguna-Acoma High School in learning how to recognize the mineral olivine in basalt, a volcanic rock, en route to a natural cross section of a cinder cone in the background. Behind the camera is geologist Larry Crumpler, leading them on the field trip to geologic features near their school in western New Mexico. Image credit: NASA/JPL-Caltech/NMMNH.

Crumpler is the lead author of the paper, which provides an overview of Spirit's traverse across the plains of Gusev Crater. He is joined by 34 other co-authors from a total of about 150 science team members. They conclude that Spirit's landing area was blanketed by basalt from an ancient lava flow that has since been pockmarked by craters and eroded by wind.

For these scientists, seeing Mars through Spirit's cameras is the next best thing to being there. Crumpler is a field geologist who has been tracking Spirit's progress in maps and survey panoramas since the start of the mission. His passion is being in the field. He loves it so much he takes Native American and Latino students, whose families have lived in New Mexico for many generations, on field trips into the deserts and mountains.

Working with Crumpler, the students learn how to recognize rocks and make geologic maps. They visit famous landmarks such as Shiprock, the frozen core of a dormant volcano in the Navajo Nation. Working in teams, they map rocks and topographic features such as volcanic dikes that radiate outward from the volcano's neck. Crumpler's love of the local geology and plant life even extends to his back yard, where he has arranged various samples to create a rock garden. He hopes to instill his love of the land and zeal for discovery in students who are the journal writers of the future, on planetary expeditions that haven't yet even been conceived.

Mars with Plants and a Blue Sky?

Geologist Larry Crumpler has created a rock garden in his backyard with native volcanic rocks and plants. The basalt mesa on the other side of the wall is part of a geologically young (approximately 150,000-year-old) series of lava flows erupted from volcanoes west of Albuquerque. Image credit: NASA/JPL-Caltech/NMMNH.

When it comes to publishing papers about the rovers, scientists work like a relay team. They take turns being the lead author.

For example, principal investigator Steve Squyres of Cornell University and deputy principal investigator Ray Arvidson of Washington University at St. Louis have led teams describing the terrain and minerals in the rocks. Matthew Golombek of NASA's Jet Propulsion Laboratory was lead author of a paper about the selection of Gusev Crater as a landing site. Ron Li of Ohio State University has led teams describing measurements that pinpoint the rover's position on a topographic map.

These authors, and many others, are cited in subsequent papers. This way, each scientist gets credit for contributing to a massive undertaking that requires the talents of a lot of people. They also know which of their colleagues to consult if they have questions. Individual papers often list dozens of contributors.

Learning About Lava

Studying a lava flow next to their high school are, from left, geologist Larry Crumpler, students Mark and Jay, and teacher Joe Aragon from Acoma-Laguna High School in New Mexico. Image credit: NASA/JPL-Caltech/NMMNH

Magnificent images sent to Earth by the Mars rovers are more than beautiful to the eye. Each image from the rover's panoramic, navigation, and hazard-avoidance cameras and microscopic imager provides important data about Mars. Scientists use the data to gauge distance, count the rocks and sand grains of a certain shape or size, and examine the boundaries between geologic features. For example, they determined that the hills are older than the surrounding plains because the rocks of the plains overlap and gradually thin out on top of the underlying rock of the hills.

Even for people who are not scientists or engineers, it can be an awe-inspiring experience to remember that the pictures come from a planet hundreds of millions of miles away. Humans have not yet been to Mars and could not walk on its surface without life support. Mars is mostly still an unexplored place.

"If there had been glossy color journals in the days of the Lewis and Clark expedition, they, too, would have been on the covers of magazines for a long time after setting off on their trek," says Crumpler.